EghtesadOnline: A top White House official warned on Thursday of “grave consequences” from any miscalculation by Turkish forces fighting U.S.-backed Kurdish militants in Syria.

NATO ally Turkey should be mindful of conflict with proxy forces especially when there might be U.S. advisers in the area, Tom Bossert, U.S. homeland security adviser, said on Thursday at the World Economic Forum in Davos, Switzerland.

Ilnur Cevik, a chief adviser to Turkish President Recep Tayyip Erdogan, said the two allies risk facing-off over the Syrian town of Manbij, where U.S. military advisers support Kurdish fighters that Turkey considers part of a terrorist group.

The remarks risk further escalation between the two countries with conflicting interests in Syria. While the U.S. has backed predominantly Kurdish forces in its fight against Islamic State, Turkey’s military wants them away from the country’s southern border.

The dispute came to a head earlier this month when Erdogan said the military would go after Kurdish militants in Syria despite U.S. objections. President Donald Trump warned Turkey on Wednesday against expanding its military offensive in Syria, cautioning that such action could lead to direct conflict with U.S. forces.

“I hope NATO’s not fighting itself,” Bossert said. “I think the idea here is that Turkey has got legitimate security concerns,” Bossert said in reference to Syrian Democratic Forces, a U.S.-backed group that is dominated by Kurdish militants considered by Ankara to be part of a terrorist organization.

Erdogan “is a NATO member and I think he’s going to remain committed to that as he sits back and thinks about the implications of his decisions,” he said.